Height and Weight Calculator

Body Mass Index (BMI) Calculator

Metric (kg, cm) Imperial (lbs, inches)

Your BMI will appear here.

function updateUnitLabels() { var unitSystem = document.getElementById("unitSystem").value; if (unitSystem === "metric") { document.getElementById("weightLabel").innerHTML = "Weight (kg):"; document.getElementById("heightLabel").innerHTML = "Height (cm):"; document.getElementById("weightInput").placeholder = "e.g., 70"; document.getElementById("heightInput").placeholder = "e.g., 175"; } else { document.getElementById("weightLabel").innerHTML = "Weight (lbs):"; document.getElementById("heightLabel").innerHTML = "Height (inches):"; document.getElementById("weightInput").placeholder = "e.g., 150"; document.getElementById("heightInput").placeholder = "e.g., 69"; } } function calculateBMI() { var weightInput = document.getElementById("weightInput").value; var heightInput = document.getElementById("heightInput").value; var unitSystem = document.getElementById("unitSystem").value; var bmiResultDiv = document.getElementById("bmiResult"); var weight = parseFloat(weightInput); var height = parseFloat(heightInput); if (isNaN(weight) || isNaN(height) || weight <= 0 || height <= 0) { bmiResultDiv.innerHTML = "Please enter valid positive numbers for weight and height."; return; } var bmi; var category; if (unitSystem === "metric") { // Height in meters for calculation var heightInMeters = height / 100; bmi = weight / (heightInMeters * heightInMeters); } else { // Imperial // BMI = (weight_lbs * 703) / (height_inches)^2 bmi = (weight * 703) / (height * height); } if (bmi = 18.5 && bmi = 25 && bmi <= 29.9) { category = "Overweight"; } else { category = "Obese"; } bmiResultDiv.innerHTML = "Your BMI is: " + bmi.toFixed(2) + "Category: " + category + ""; } // Initialize labels on page load window.onload = updateUnitLabels;

Understanding Your Body Mass Index (BMI)

The Body Mass Index (BMI) is a simple numerical measure that is widely used to categorize whether a person's weight is healthy in proportion to their height. It's a screening tool that can indicate potential weight problems for adults, but it does not diagnose the body fatness or health of an individual.

How BMI is Calculated

The BMI is calculated using a straightforward formula that takes into account your weight and height. There are two primary formulas depending on the unit system you use:

• Metric Formula: BMI = weight (kg) / [height (m)]²
• Imperial Formula: BMI = [weight (lbs) / height (inches)²] x 703

Our calculator allows you to easily switch between these two systems to get your BMI result.

Interpreting Your BMI Results

Once you have your BMI, it falls into one of several categories:

• Underweight: Less than 18.5
• Normal weight: 18.5 – 24.9
• Overweight: 25 – 29.9
• Obese: 30 or greater

These categories are general guidelines. For example, a BMI of 22.5 would be considered within the "Normal weight" range, while a BMI of 28.0 would fall into the "Overweight" category.

Limitations of BMI

While BMI is a useful screening tool, it's important to understand its limitations:

• Muscle Mass: BMI does not distinguish between muscle and fat. Athletes or individuals with high muscle mass may have a high BMI, but low body fat, meaning they are not overweight or obese.
• Age and Sex: BMI ranges are generally the same for men and women, but body composition changes with age. Older adults may have less muscle mass and more fat than younger adults, even with the same BMI.
• Ethnicity: Different ethnic groups may have different health risks at the same BMI.
• Body Fat Distribution: BMI doesn't account for where fat is stored. Abdominal fat (around the waist) is associated with higher health risks than fat stored in other areas.

When to Consult a Healthcare Professional

Your BMI is just one piece of information about your health. If your BMI falls outside the "Normal weight" range, or if you have concerns about your weight, it's always best to consult with a healthcare professional. They can perform a more comprehensive assessment, considering factors like your body composition, waist circumference, diet, physical activity levels, and family history, to provide personalized advice.

Examples of BMI Calculation:

Example 1 (Metric):

• Weight: 70 kg
• Height: 175 cm (1.75 m)
• Calculation: 70 / (1.75 * 1.75) = 70 / 3.0625 = 22.86
• Result: BMI of 22.86 (Normal weight)

Example 2 (Imperial):

• Weight: 180 lbs
• Height: 72 inches
• Calculation: (180 * 703) / (72 * 72) = 126540 / 5184 = 24.41
• Result: BMI of 24.41 (Normal weight)

Use the calculator above to find your own BMI and get a quick insight into your weight status!